Living with multiple sclerosis (MS) is already tough, but imagine having trouble with the simplest of tasks because of an unpredictable and frustrating symptom — ataxia, an inability to control muscle movements because of nerve damage. From walking and writing to simply sitting upright, ataxia can make even the smallest movements feel like a challenge.
People living with multiple sclerosis commonly experience ataxia as a symptom of MS. According to the Multiple Sclerosis Trust, ataxia affects about 4 out of 5 people with the condition.
Having trouble controlling your muscles due to ataxia can cause difficulties in many parts of your life — how you walk, talk, and eat, and even how you feel emotionally.
Ataxia refers to a loss of coordination due to nerve damage. Although you will notice its effect on your muscles, ataxia is not caused by muscle weakness.
The causes of ataxia in multiple sclerosis relate to how the condition damages nerve cells. MS is an autoimmune disorder where the immune system mistakenly attacks the myelin sheath surrounding and protecting nerve fibers in the brain and spinal cord — a process called demyelination. When the myelin sheath is damaged, the nerves can’t function as well. As the disease progresses, more nerve cells are damaged. When nerve fibers in the brain are demyelinated, it can cause lesions (areas of tissue damage) that impair your ability to coordinate movement.
Ataxia can be a symptom of another disease (such as MS) or a condition on its own. Ataxia can be inherited or caused by factors like medication side effects, alcohol misuse, head injury, tumors, or other medical conditions.
There are three main types of ataxia — cerebellar, sensory, and vestibular ataxia.
The cerebellum is found at the base of the brain and connects to the brainstem. The cerebellum’s main job is to coordinate muscle movements you control, such as moving your arms and legs. Cerebellar ataxia can occur when any part of the cerebellum is damaged. The way cerebellar ataxia affects your body depends on which specific area of the cerebellum has been damaged.
Sensory ataxia refers to a condition when you can’t sense the location and movement of your body in space — called proprioception. It occurs when there is damage to the parts of the spinal cord or brainstem that inform your brain about the body position, and you may have trouble determining where your limbs are in relation to your body.
The vestibular system is responsible for your sense of balance. It involves your eyes, inner ears, and the muscles of your core (abdomen, pelvis, and back). It can occur when the vestibular system (in the brainstem) is damaged. If you have vestibular ataxia, you may experience a loss of balance, vertigo and dizziness, nausea and vomiting, frequent falls, and vision problems.
Your symptoms of ataxia will depend on how your spinal cord, brainstem, and cerebellum are affected by MS. Here are eight ways ataxia may show up for you.
When ataxia damages the nerves involved with muscle tone (spasticity) and balance, it can affect the way you walk — also called your gait. Changes in balance can make it appear as if you are drunk when you walk.
Walking and exercising less often can cause atrophy (the loss of muscle mass) and create further changes in your gait.
Common gait changes with ataxia include:
Ataxia can make you feel more clumsy and more likely to fall. People with ataxia have several risk factors for falls, including:
Studies show that between 50 percent and 70 percent of people with MS reported falling in the past two to six months. About 30 percent of people with MS are injured at some point from multiple falls.
A tremor is an uncontrolled shaking movement. Tremors can affect the head, vocal cords, torso, arms, and legs. They can make daily activities — such as getting dressed or eating — difficult to complete.
Studies have found between 25 percent and 58 percent of people with MS experience tremors. In MS, tremors are usually not severe.
Two types of tremors are common in MS: intention tremor and postural tremor.
An intention tremor usually gets worse when you’re moving purposefully, such as reaching out to grab an object. A postural tremor can happen when you’re supporting your body against gravity — so you’d shake while standing or sitting up, but not as much when lying down.
Speech problems can result if there is damage in the parts of the brain that control physical speaking or the cognitive processes to choose your words. Dysarthria is the name given to ataxia of speech. Dysarthria is caused by abnormal coordination of the muscles and nerves that move your mouth, tongue, and diaphragm.
Changes in speaking with MS can include:
Damage to nerve cells in the cerebellum can cause dysfunction in several areas that are needed to eat. If the nerves controlling the muscles of the mouth, tongue, or esophagus are damaged, it may cause dysphagia (trouble with chewing or swallowing). Some people may notice it’s especially hard to swallow thin liquids like water. Numbness can also increase the possibility of biting your tongue or cheek.
If you have a tremor, it may be difficult to bring food to your mouth. Adaptive devices such as weighted utensils can make it easier.
Additionally, about a quarter of people living with MS lose some of their sense of taste. It can be harder to eat when food isn’t enjoyable.
Vision problems are often the first symptom people with MS notice. Ataxia can cause blurred or double vision, making it hard to read or watch moving objects. It may also cause involuntary jittery eye movements called nystagmus.
Multiple sclerosis and ataxia can cause fatigue. Fatigue is one of the most common symptoms of MS. Although fatigue is difficult to measure, most people with MS experience fatigue, even if they have minimal limitations in other areas.
The way ataxia causes fatigue is unknown, but it could be related to the effort it takes to compensate for a lack of coordination and interrupted sleep.
People with MS are more likely than the general population to experience depression. This might be due to the stresses of adapting to a chronic illness, or it could be a direct result of ataxia. The cerebellum is involved in some forms of thinking, so damage to this part of the brain may result in mood changes.
A doctor who specializes in treating diseases of the brain and spinal cord — called a neurologist — may be able to help you improve your symptoms of ataxia. If you experience any of the symptoms described in this article, talk to your health care team.
There isn’t a specific treatment for ataxia. Symptoms may improve by treating multiple sclerosis, the underlying cause of ataxia, with disease-modifying therapies. This kind of treatment is used to slow down or modify the progression of a disease
Some therapies can help you better control your muscle movement. These include:
Adaptive devices can make life with ataxia easier. Examples of adaptive devices include:
Ataxia is a common symptom of MS that can significantly affect your quality of life. There are many types of treatment to manage ataxia, such as physical therapy, medication, and assistive devices. Your neurologist can help you find the best way to treat your MS and refer you to specialists who can help you adapt to your abilities.
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